Asthma and allergies

Some asthma is caused by allergies.

The most common allergens that cause asthma are:

  • dust mites
  • dander from animals (skin, scales and fur)
  • rodent urine
  • insect debris
  • food dust
  • pollens
  • moulds.

Allergy tests

There are tests to find out whether your asthma might be caused by an allergy, such as a skin prick test or blood test.

Skin prick tests are generally not used for children under the age of 3, as they don’t give reliable results in young children.

For more information about testing, talk to your doctor. 

Dust mites

Dust mites are a common allergen that cause asthma. They’re found in every home.

There are some things you can do to cut down your exposure to dust mites and their droppings:

  • Get bedding covers that provide a barrier to dust mites. (This is the single most effective measure you can take.)  Contact your local Asthma Society to find out where you can get these covers.
  • Consider removing as much fitted carpet as possible, especially in the bedrooms.
  • Vacuum cleaners won’t get rid of dust mites, but they do suck up dust mite droppings. Vacuum at least once a week and if possible, use a HEPA filter system in your vacuum cleaner.
  • Dust regularly with a damp cloth.
  • Hang your washing in the sun to dry, rather than using the dryer.
  • Air blankets and loose rugs on the washing line regularly.
  • Try not to store things under the bed or on top of wardrobes.

For children with asthma:

  • Put their soft toys in the deep freeze for at least 24 hours every 3 weeks. Use washable soft toys and avoid fluffy toys if possible.
  • Avoid using sheepskins (especially for a baby’s bedding).
  • Don’t put young children on a bottom bunk.


Wind-pollinated plants tend to be more likely to trigger asthma than plants that are pollinated by insects or birds. 

Problem plants include pines, oaks, wattles, birches, grasses, plantains, olives and privets.

Flowers such as daisies, marigolds and chrysanthemums can also be triggers.

Here are some tips to help reduce your exposure to pollen:

  • Use pollen forecasts to help you work out when you may be at risk.
  • Stay indoors, if possible – particularly on windy days when the pollen count is high.
  • Keep windows closed when the pollen count is high, especially when you’re in the car.
  • Get someone else to mow your lawns and trim your hedges.
  • Avoid organic mulches: use gravel mulch instead. Be careful with potting mix as breathing in mould spores can be an asthma trigger. 
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